Overview - Alcatel-Lucent 7450 Quality Of Service Manual

Ethernet service switch; service router; extensible routing system

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Overview

The policing option, when enabled, applies only for ingress traffic. Similarly, the shaping

option, if enabled, applies only for egress traffic. For example, if a traffic descriptor has both

options, policing and shaping enabled, the policing option is enforced for the ingress traffic,

while the shaping option is enforced for the egress traffic. The policing option is valid for all

service categories. The following ATM service category conformance definitions are

ATM Queuing and Scheduling

The router provides a per-VC queuing architecture in the ATM-capable MDAs. In the egress

direction towards the ATM port, the scheduling priority at the ATM layer is as follows:

P0_1 - CBR, UBR

P0_1andS0_1 – VBR.1

P0_1andS0 – VBR.2

P0_1andS0_Tag – VBR.3

Ingress shaping — ATM layer ingress shaping is not supported. Packet level shaping

is supported as per the service ingress QoS policy applied to the ATM SAP.

Egress shaping — ATM layer egress shaping is supported for CBR, rt-VBR, and nrt-

VBR VCs. A CBR VC is shaped to a single leaky bucket with parameter PIR. A rt-

VBR VC or a nrt-VBR VC is shaped to two leaky buckets with parameters PIR and

{SIR, BT}, where BT is the Burst Tolerance and is a function of the MBS parameters

configured by the user in the traffic descriptor.

In the egress direction, packet level shaping is supported as per the service egress

QoS policy applied to the ATM SAP.

CBR VCs are scheduled with strict priority over all other service categories

rt-VBR VCs are scheduled next with strict priority over nrt-VBR and UBR VCs.

nrt-VBR shaped VCs are scheduled next with strict priority over nrt-VBR unshaped

VCs and UBR VCs.

Quality of Service Guide